Technical Field
Embodiments described herein relate to storage systems, and more particularly, to techniques for detecting conflicting storage capacity between a host and a storage system and characterizing the potential space reclamation.
Description of the Related Art
As computer memory storage and data bandwidth increase, so does the amount and complexity of data that businesses daily manage. Large-scale distributed storage systems, such as data centers, typically run many business operations. A data center, which also may be referred to as a server room, is a centralized repository, either physical or virtual, for the storage, management, and dissemination of data pertaining to one or more businesses.
A file system may be defined as the part of an operating system which translates file-based accesses into logical block addresses corresponding to storage locations on one or more storage devices. A file system may also be defined as software which organizes sectors of one or more storage devices into datasets (e.g., files, volumes), directories, and/or folders. The term “file system” may also refer to the organized datasets, directories, or folders. Commonly used file systems include File Allocation Table (FAT), New Technology File System (NTFS), Network File System (NFS), Hierarchical File System (HFS), International Organization for Standardization (ISO) 9960, High-Performance File System (HPFS), Unix File System (UFS), Veritas File System (VxFS), Virtual Machine File System (VMFS), Third Extended Filesystem (Ext3), Fourth Extended Filesystem (Ext4) and others.
In data centers utilizing block-based storage arrays, the file system is typically managed by the host and not by the storage array. Accordingly, the storage array does not know when a file has been deleted or moved from a storage volume and therefore does not know when or if to release the space. This situation is especially detrimental in thinly-provisioned environments where that space could be immediately allocated to another device or application or just returned to the pool of available storage.